Winter a no-show so far

By Reginald Stanley. Posted January 11, 2014, 6:19 PM.

The new year has started out warm and dry for the region, due to a stationary high pressure ridge over the area. This has brought a long stretch of unseasonably warm, dry, and often windy weather to the region. The last rainfall occurred early on December 20th, 2013 - nearly a month ago.

Rainfall for the 2013-14 season to date has been well below normal all across the state, with a series of generally weak storms between October and December. Since July 1st, Temecula has recorded a meager 1.82" inches, almost five inches below the normal 6.69" inches. San Diego's City Heights neighborhood as well as Simi Valley have both not exceeded 1" so far this season. The location with the highest season total-to-date is San Bernardino with 4.45" inches recorded since July 1st. Anza was not far behind with 4.33", which benefited greatly from last summer's abundant monsoons there. Most WeatherCurrents stations have season totals between 1" and 3" as of January 11th, 2014. The water year ends on June 30th.

Extended dry periods during winter are rare, but there have been notable examples of this in the past. In the 2005-06 rain season, very little rainfall fell between October 2005 and February 2006, with the exception of a wet New Years Day storm. Most of the season's rainfall that year fell between late February and May (especially March). Dry periods have occurred even in wetter winters. In Temecula, December 2000 was warm and very dry, with only 0.02" recorded there. January 2003 was unusually very warm - one of the warmest Januarys on record - and also very dry. January 2009 was similarly warm and dry.

The 2013-14 winter has been characterized by neutral conditions in the equatorial Pacific - the absence of an El Nino or La Nina phenomenon. Added effects from the Pacific Decadal Oscillation (PDO), which has been in a cold phase since 2008, are consistent with historic trends of a dry winter in Southern California. This would be the second consecutive "neutral" winter, and third consecutive dry winter if conditions do not improve. Other long-term droughts occurred in the region from 1945-1951, 1987-1991, 1999-2004, and 2006-2010. The current drought began in 2012.

The wettest months of the year in the region are typically January, February and March. December is the coldest, on average.